EXAMPLE 9.5

Two-way table of vaccination opinions and political party preference. To compare the frequency of vaccination opinions across political party preference, we examine column percents. Here they are, rounded from the output in Figure 9.1 for clarity:

The “Total” row reminds us that 100% of the Democrats and Republicans have been classified as either thinking that vaccinations should be required or not. (The sums sometimes differ slightly from 100% because of roundoff error.) The bar graphs in Figure 9.2 compare the percents. The difference between the percents of adults who think vaccinations should not be required is reasonably large (24% for Democrats versus 35% percent for Republicans).